I think it’s time for a Shruti-1/Shruthi-1 review!

December 7th, 2010

Introduction to this review

The Shruti-1 came out about one year ago, and was a bit of a revolution for me. I had never seen something like that, and to be fair, I had never even thought something like that could be possible: a small, fully functional and standard-compliant synth for a ridiculously low price. There was and is only one twist to the whole deal: you had to solder the whole device yourself, with only an online guide to help you. While, for some people, this might be a real deal-killer, for me (as for many others) it was added value. The idea of creating an instrument with my own hands, albeit following the creators directions, was really intriguing me. Even better that the kit didn’t include any casing for the instrument, giving me a good reason to create my own! After having studied design for years this was a challenge I took on wholeheartedly!

Mutable Instruments (or Olivier if you prefer) produced only 80 kits for the Shruti-1, since this one was based on the hard-to-find Curtis CEM3379 filter, then moved on to create a new, even better synth called the Shruthi-1 which features more horsepower sound-wise and a couple of different filter options, including a really good one made from scratch by Olivier himself.

Now that I have bought, built and used both devices for some time, I thought it would be about time to write a little review about them, so here we go:

The Shruti-1

Building process: the building process is pretty straight forward, the guide does a good job in helping novices to get the whole thing done in a few hours. Of course you should know how to solder, and have a basic understanding about how electronics work, but that’s all. I only had assembled an Atari Punk Console before that, and was able to build the Shruti-1 without a problem. I think Olivier made a pretty good job in limiting the needed material to the bare minimum, the whole synth is made up of just 2 small pcbs, uses standard components and can be assembled at home with just a small soldering iron (15W) and a multimeter to check if you’re doing it right. A hammer is needed only for certain, peculiar case designs.

Features: The Shruti-1 is monophonic and midi controlled. It features 2 digital oscillators with waveforms ranging from the classic pulse, triangle and sawtooth to more complex Wavetables (2-operator FM, 8-bit stuff, an aliased square, noise, a low-fi formant wave, and some more), provided by an 8-bit ATMega328p chip (as seen on some Arduino boards). To these you can add a square or triangle sub-oscillator and some noise.

The filter is based on an old-school Curtis CEM3379 filter IC, and also has input capability (you can use the Shruti-1 as a external filter for other instruments).
The software is kept quite simple but offers two envelope generators, two LFOs, a simple but poweful modulation matrix, the possibility to process incoming control voltages, a step sequencer which can be assigned in the matrix, an arpeggiator, portamento, and even the possibility to use different tunings. For live play there is a special “performance page” where you can group the 4 most used parameters for quick and easy live tweaking of the sound.

The Shruti-1 is also pretty hackable, thanks to a special “hack-me” header you can add external control voltages, potentiometers or sensors. There is even a website where you can customize the firmware on your device, choosing for instance which wavetables should be included, or which should be the init values.

Sound: Regarding the oscillators, the sound leans more towards the dirty lo-fi chiptuneish side. Add to that the capability to sync the oscillators, ring modulate them or (even better) apply XOR modulation and you get some really nasty, screaming sounds out of it!

But now comes the filter! The CEM3379 is an analogue filter chip, which was used in synths/samplers like the ESQ1 or the Prophet 2000 and performs as expected: amazingly well! Turn down the knob and it really turns the sound of the Shruti-1 into a soft, warm musical beauty, crank up the resonance and it can get quite nasty! Thanks to this filter you can produce a really wide spectrum of sounds with this little device: 8-bit madness, classic analogue sounding leads and basses, soft and warm pads, but also weird drones, sound effects and noisy stuff with a certain Trent Reznor vibe to it.

In use: one of the biggest strenghts of the Shruti-1 is it’s easy but powerful interface. I really think that it manages to find a great compromise between features and ease of use. You can learn how to program it in under 30 minutes, which makes it great also for those people who are not that experienced with synths. To interact with it you have: 5 buttons to navigate between the “pages” and four knobs to tweak the parameters (which, of course are 4 per page). There is a total of 12 pages, so some buttons are also used to cycle between multiple pages, a series of leds is used to show the user which one is active.

In my experience the Shruti-1 excels with basses (thanks to the filter), arpeggios and weird noisy stuff. Thanks to the modulation matrix and step sequencer you can also create some pretty complex arpeggiator lines. Despite its size it is capable of great presence even when put together with acoustic instruments.
Patches can be stored in an internal memory, but only 16 “slots” are available. Fortunately every time a patch gets saved the Shruti-1 sends out a sysex dump so you can store your patches on your computer via MIDI.

The only issues I have found are that the arpeggiator may to act a bit weird sometimes, when used in conjunction with an external midi clock and that the envelopes click at very low settings. I solved the latter by adding a small capacitor to the circuit, as suggested on the mutable instruments forums. Which shows another positive thing about this synth: the great community behind it!

Conslusions: The Shruti-1 is an amazing synth, small, powerful, easy to learn and to use, with a unique sound.
I think what makes it so interesting is the vividness and warmth of it’s analogue circuits combined with the roughness and aggressiveness of the 8 bit digital oscillators.
There is really nothing I am missing in a device of this class and size. Of course some real FM would have been nice, sometimes you wish you had more than 16 slots to save your patches, and maybe an arpeggiator with user definable patterns would have been great. Actually all of these features could be implemented by hacking the firmware, but that’s not even necessary, most of what you could be missing in the Shruti-1 is present in its successor: the Shruthi-1!

The Shruthi-1

The naming might be a bit confusing at start. The newer Shruthi-1 just adds one H to the name in a position where you don’t really notice it. I still wonder why Olivier chose to give his new synth such a confusing name (UPDATE: the mystery has been cleared: it’s all been explained here: http://mutable-instruments.net/shruthi1/faq) . This is probably the only bad thing one can say about the Shruthi-1, because in every other aspect, it is an even greater device than its predecessor. Or to say it with different words: it’s just like the old one, just better in every aspect!
Building process: building the Shruthi-1 was just as easy. The guide was maybe a bit less detailed than the first one, but still good enough to get even the total noob to complete the building process without major problems. This time you can even get a case for the Shruthi-1, which is certainly a great option for those who don’t want to mess with prototyping, drawing and lasercutting (and spending some good money on it). For just 20 € you get a nice and shiny lasercut and engraved transparent plexy case.

A little comparison: While assembling the Shruthi-1 I could not help but compare it to the SammichSID, which is another DIY synth I built. Of course the two devices are quite different: the SammichSID is based on the popular MidiboxSID schematics and software and uses two MOS SID chips (from the Commodore64) adding the necessary hardware/software to it to make them usable as a synth, on the other hand the Shruthi-1 has been created completely from scratch both hardware and software-wise. On the other hand they have a good amount of similarities: sandwitch-style design (one pcb on top of another to be as compact as possible) more or less same form factor and price, both come as a kit, have roots in the chiptune scene and are monophonic (I know that’s not 100% true, but bare with me on this one) so let’s see how they compare.

Apart from the sound, which depends a lot on personal taste, there’s things where the SammichSID is better, and others where the Shruthi-1 clearly wins. The case of the SammichSID is a pretty simple but clever design, they managed to hold everything in place with just the 4 screws that keep the pcbs together, everything has been designed in a way so that the parts just fits together with absolute precision, it was a total revelation to assemble it and I often wondered how they managed to get it all to work in such a precise way.

The Shruthi-1 is a bit less precise in its design, for instance on the basic case there is no on/off switch, the LCD just sticks out of the frontplate, the holes for the MIDI connectors are bit out of place, you need 4 additional screws to keep it together and the way the two pcbs are connected might also be improved, since the provided parts are a bit too short.

On the other hand, the Shruthi-1 manages to pack more power in a slightly smaller case, is easier and quicker to assemble, has a much better designed interface and, like the Shruti-1 has 4 potentiometers for tweaking the parameters (great when playing live), while the SammichSID only has one encoder to do everything. Some features are a bit more powerful on the SammichSID (like for example the modulation matrix) but most of them are a bit complicated to use. Olivier’s synth has a more user-friendly approach, which is a great plus in my opinion.

Finally the Shruthi-1 has a pretty good sounding and capable analogue filter (you can even choose which one you want to have).

Features: The Shruthi-1 has more or less the same features as its predecessor: 2 oscillators plus a sub-oscillator and a noise generator, envelopes, LFOs, modulation matrix, step sequencer, arpeggiator and so on.

So what’s different? First of all you get more wavetables (I guess it’s due to the CPU upgrade, which is an ATMega644p), a lot more in fact! Sampled single cycle waves from acoustic instruments, phase distorted waves from Casio keyboards, more 8-bit sounds, even samples from a human voice! The sub-oscillator now also works as a transient generator (which you can use to add some punch to your sounds, or for percussive patterns). The oscillators can be mixed with a “fuzz” algorithm, which acts like a waveshaper. There’s more modulators and destinations in the matrix. The arpeggiator and step sequencer have been complemented with a pattern sequencer (you can program a pattern, and transpose it by pressing a key on the keyboard) and a rhythm sequencer, plus there is various modes that enable you to use one or the other in different ways. Midi out not only works as a thru as in the Shruti, but can now also output the sequencer notes.

The Memory is now enough to hold up to 80 presets, you can perform a “global dump” for backup purposes, and you can even polychain more Shruthi’s if you have them.

Sound: the main difference sound-wise is certainly given by the filter. It should be noted that Olivier chose to go for a kind of modular approach here, since you can choose which filterboard to use. Right now you have 3 options: go for a CEM 3379 for filtering, but Olivier will only provide the board not the the actual chip for it, add a SSM2044-based filter (the SSM2044 is the filter chip used in the legendary PPG Wave and other vintage synths, here as well you would have to find the chip yourself) or choose Olivier’s own SMR-4 filter. The last seems the easiest and most logical solution. Olivier did a great work in creating this filter, which sounds incredibly musical. A bit softer and cleaner when compared to the Curtis, but still capable of some screaming if the resonance is cranked up high enough. It should be noted that the filter has to be manually tuned before use, which might take some time, but is a great learning experience.

Overall the sound of the Shruthi-1 with the SMR-4 board is somehow similar to the Shruti-1, though a bit more on the “musical” side due to the different filter characteristics. To me the main difference is that it adds more possibilities thanks to the transient generator and the many new waveforms, greatly widening the palette of possible sounds.

In use: I haven’t had as much time to play with it as with the old Shruti-1, but one thing was immediately clear: it’s just as easy to handle, and an equal joy to play. The navigation concept has been thought out well, and feels like a natural evolution of the old model, the new functions have been logically placed and integrate well with the existing parameters. I have been using this device a couple of times in a live improvisation situation and it really adds a special touch to it, and is capable of unexpected presence on the higher registers and can work really well to provide a good bass fundament or an arpeggiated synthline to improvise on.

Conslusions: The Shruthi-1 is a great improvement to the old model, and feels a lot more polished and mature in many aspects. The winning aspects are the same as for the Shruti-1: warm analogue sounds meets 8-bit digital weirdness, all well packaged in an easy to use interface.
The Shrut(h)is are the synths I end up programming and experimenting with the most, if I had to sell all of my gear and could keep just one device, I would choose one of them (and having a hard time in deciding which one it should be). I really think if you’re not afraid of getting your hands a bit dirty get one! It is a must for the synth lover (pro and enthusiast alike)!

More about the Shruthi-1: http://mutable-instruments.net/shruthi1b

Music made with the Shrut(h)i-1: http://soundcloud.com/groups/mutable-instruments-shruti-trax

Other synths like the Shrut(h)i-1: SammichSID | Meeblip | AVR Synth

The foto of me with the hammer was made by Sbrizz

Creative Commons License
The Shrut(h)i-1 review by Hannes Pasqualini is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.
Based on a work at weblog.papernoise.net.

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